Haemocytometer is a device which was originally used to count blood cells. It is now used to count other cells and many types of microscopic particles as well. It consists of a thick glass microscope slide with a rectangular identification that creates a chamber. This chamber engraved with a laser etched grid of perpendicular lines. The device is carefully grafted so that the chamber is also known. Therefore it is possible to count the chamber in which the number of cells or particles in a specific volumes of fluid and there by calculate the concentration of cell in the fluid overall.